A Genetic Analysis of Species Differences in Columbidae

VIDENCE was presented in a previous paper (IRWIN and his col-E laborators 1936) that certain of the antigenic charactefs of the red blood cells, by which Columba guinea is differentiated from C, livia domestics, had been obtained as units following, respectively, backcrosses of the species-hybrid and backcross hybrids to livia.Since a segregation of the cellular characters peculiar to Pearlneck (Streptopelia chinensis)2 as contrasted with Ring dove (Streptopelia risoria) has been observed in individuals of the first and second backcrosses to Ring dove (IRWIN and COLE 1936, 1937), it would be anticipated from the results in the Columba species that isolation of the specific Pearlneck components may be accomplished.Investigations to this end are reported in this paper.References to earlier and related publications have been made previously. EXPERIMENTAL PROCEDUREThe cellular characters under study are recognizable a t present only by immunological techniques.The details of these methods have been adequately described elsewhere (IRWIN and COLE 1936, 1937)~ but a brief exposition of the principles involved may be helpful.The antiserum obtained from a rabbit which has been injected with the erythrocytes of a particular species, as Pearlneck, will not by direct agglutination tests differentiate the cells of the donor species from those of any other species of the same family.That is, the highest dilution of antiserum (that is, the titer) which will cause clumping of the homologous cells will usually produce clumping also of the cells of other species of the same genus or family.However, if the antiserum for Pearlneck, at a relatively low dilution depending upon its titer, is mixed with an excess of the cells of Ring dove or some other species, it becomes by the absorption a differentiating "reagent," or "test-fluid," which will agglutinate the homologous but not the absorbing cells.Usually, following the absorption of anti-Pearlneck serum by Ring dove cells, the titer of the absorbed serum for Pearlneck cells is reduced slightly from that of the unabsorbed antiserum.Paper No. 244 from the Department of Genetics, Agricultural Experiment Station, University of Wisconsin.This investigation was supported in part by grants from The Rockefeller Foundation, and from the Wisconsin Alumni Research Foundation.e I n former papers, Pearlneck was designated as Spilopelia chinensis.Recently PETERS (1937) has proposed that this species be included in the genus Streptopelia.